Intrusion Detection Systems (IDSes) are software and/or hardware components that monitor the events in a computer or in a network and analyze the activities for signs of possible violations of computer security policies. There are various kinds of IDS each addressing a different aspect of computer security. A Network IDS (NIDS) attempts to identify unauthorized, illicit and anomalous behaviors based on network traffic, whereas a host IDS (HIDS) attempts to identify violations of the security policies on a specific device.